As the U.S. Congress prepares to debate military action against the Syrian regime, rebel commanders and fighters on the ground say that it would take a decisive strike to aid them in their fight.

Salim Idris, the chief of staff of the Free Syrian Army's (FSA) Supreme Military Council, says he hopes for a devastating strike against the regime, not just a "slap on the wrist" with little to no impact.

"There is no more room for excuses from the international community after this massacre," says Idris, a former brigadier general in Assad's army who defected in July 2012.

Abdel Jabbar Akaidi, the FSA's chief for Aleppo province, enjoys wide support among rebel ranks. He says that a weak campaign could do more harm than good. "If the strikes target the airports, Scud missile launchers, and command and control headquarters, then they will cripple the regime," he tells Syria Deeply.

On the other hand, "a light strike would be worse than doing nothing. If it's not the death blow, this game helps the regime even more. The Syrian people will only suffer more death and devastation when the regime retaliates."

Meanwhile, Syrian army troops are preparing for the potential strike and working to limit its effects. Sources close to the Assad regime say the army has evacuated its top officers from the military bases that are expected to be among the targeted locations. Those include the Brigade 155 missile base, home to the elite fourth armored division, which is headed by President Bashar al-Assad's brother Maher.

Some of the Ministry of Defense's scientific research centers, where chemical weapons are manufactured and developed, have also been emptied of key staffers, along with defense laboratories in the northern city of Safira, outside Aleppo.

As the Syrian military anticipates an attack, there has been a wave of new defections among lower ranking troops. But those defectors are mostly motivated by fear, not a desire to join the nearly 2.5-year-old rebellion.

"There are a good number of defections of people afraid of an American strike, but we don't know the exact number," says Abu Hussein, 28, an FSA lieutenant based in the Damascus suburbs. "They are in hiding," and not joining the rebel fighters.

"The number one reason is that they are afraid of a Western strike," says Akaidi, adding, "you also have people within the regime who felt the war entered a different phase with the killing of children in such a way."

U.S. intelligence reports based on the testimony of doctors, activists and journalists on the ground claim that more than 1,400 people, including 426 children, died in the Aug. 21 chemical weapons attacks on the Damascus suburb of Moadamiyat al-Sham and eastern Ghouta.

But civilians and fighters living in rebel territories remain skeptical of U.S. motives for intervention. While many FSA commanders are still holding out for Western support, rank and file soldiers are cynical.

"The U.S. will not topple Assad because it is in their interest to let the regime continue fighting with the jihadists," says a fighter named Ahmed, referring to groups like ISIS and Jabhat al-Nusra, which are becoming increasingly influential on the ground.

Abu Hussein says that the FSA and regular citizens "think the Americans informed the regime of the strike targets in advance.

"We're not going to benefit from a strike at this point, since the regime had time to prepare itself. The army and security forces have transferred their men from their headquarters and bases and stationed them in schools and hospitals and civilian areas. The only way it would be useful now is if they dealt a major blow."

Like many of his countrymen, the defected lieutenant is not holding his breath.